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'MOUND DESIGN WORK SHEET(For Flows up to 1200 d) <br /> A. Average Design FLOW A-1: Estimated Sewage Flows In Gallons per Day <br /> number o <br /> Estimated r1 0 gpd (see figure A-1) bedrooms Class I class II class III Class Iv <br /> or measured x 1.5 (safety factor) _ — gpd 2 300 225 180 60% <br /> 3 450 300 218 of the <br /> 4 600 375 256 values <br /> B. SEPTIC TANK Capacity 5 750 450 294 in the <br /> 6 900 525 332 Class I, <br /> gallons (see figure C-1) 7 1050 600 370 II, or lu <br /> 8 1 1200 1 675 1 408 1 columns. <br /> C. SOILS (refer to site evaluation) c-1: SkptdicTaACapacities m Ilona <br /> Number of Minimum Liquid Liquid capacity with Liquid capacity <br /> 1. Depth to restricting layer= I, (�-so 1.� feet Bedrooms Capacity garbage d sptydisposal <br /> with disposal& <br /> lift inside <br /> 2. Depth of percolation tests = ), 0 feet 2orless 750 1125 1500 <br /> 3. Texture L�.A� L0 Aw 3or4 1000 1s00 2000 <br /> 5 or 1500 2250 3000 <br /> Percolation rate I),► mpi 1 i,g or 9 2000 3000 <br /> 4. Soil loading rate .4:5' gpd/sgft(see figure D-33) <br /> 5. Percent land slope (,51 <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multi ly average design flow (A) by 0.83 to obtain required rock layer area. <br /> o gpd x 0.83 sgft/gpd = Lai sgft-rco 1>o=1,o%4° <br /> 2. Determine rock layer width = 0.83 sqft/gpd x linear Loading Rate (LLR <br /> 0.83 sqft/gpd x );L- -.g d/sqft= /0 ft Mound LLR <br /> 3. Length of rock layer = area 1 width= <br /> L Y� sqft(D1) /0 ft (D2) = (o, ft < 120 MPI < 12 <br /> E. ROCK VOLUME > 120 MPI < 6 <br /> 1. Multiply rock area (Dl) by rock depth of 1 ft to get cubic feet of rock <br /> L,,% sqft x 1 ft = L,% cuft <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> � cuft 127 cuyd/cuft= aS cuyd <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons <br /> cuyd x 1.4 ton/cuyd = 3S tons <br /> `D-33: Abtaorpdon Width Sizing Table <br /> F. SEWAGE ABSORPTION WIDTH Percolation Rate LoadingRate <br /> in Minutes per Soil Texture Gallo Gallonss <br /> Absorption <br /> Inch per day per Ratio <br /> MPI uarc foot <br /> Faster than S Coarse Sand 1.20 1.00 <br /> Medium Sand <br /> Absorption width equals absorption ratio (See Figure D-33) gSne Sand <br /> amy Sand <br /> 61015 Sand):txam 0.79 <br /> times rock layer width (D2) Ito 4s lit <br /> is :5 2:0 <br /> a x_�_ft = l.�. f t lt <br /> 46 to 60 sandy a0.45 2.67 <br /> Silt Clay <br /> l.wm <br /> 61 to 120S1lty Clay 0.24 5.00 <br /> Sandy Clay <br /> Slower than 120` Clov <br /> -Sysum desisx d for d—wits—a bs aber or psrfom+soce <br />